Divorcing Language Dependencies from a Scientific Software ...
27
Divorcing Language Dependencies from a Scientific Software Library Gary Kumfert, with Scott Kohn, Jeff Painter, & Cal Ribbens LLNL VaTech
Transcript of Divorcing Language Dependencies from a Scientific Software ...
Divorcing Language Dependencies from a Scientific Software Library
Gary Kumfert, with
Scott Kohn, Jeff Painter, & Cal Ribbens
LLNL VaTech
GKK 2CASC
Language Interoperability Tool♦ You specify “interfaces” in our language♦ We generate glue code between application
and library
Part of a Component Framework♦ Enables OOP in non-OOP languages♦ Enables safe Dynamic Casting and
QueryInterface capabilities
GKK 3CASC
What I mean by “Language Interoperability”
Simulation Framework(C)
Scripting Driver(Python)
Visualization System(Java)
Solver Library(C++)
Numerical Routines(f90)
GKK 4CASC
Hand Coded SolutionsJNI
NativeSWIG
Platform Dependent
C
C++
f77
f90
Python
Java
GKK 5CASC
Objects, Virtual Functions, RMI & Reference Counting: all from Babel
f77
Java
BabelC f90
C++ Python
GKK 6CASC
Babel generates glue code
machineconfiguration
database
f77
SIDL interfacedescription
parser analyzer backendC
Python
C++
XML repositoryinterface
description
GKK 7CASC
Scientific Interface Definition Language (SIDL)version Hypre 0.5;version ESI 1.0;
import ESI;
package Hypre {interface Vector extends ESI.Vector {
double dot(in Vector y);void axpy(in double a, in Vector y);
};interface Matrix {
void apply(out Vector Ax, in Vector x);};class SparseMatrix implements Matrix, RowAddressable {
void apply(out Vector Ax, in Vector x);};
};
classexceptioninterfacepackage
GKK 8CASC
Software to be “divorced” from its language dependence
Scalable parallel linear solvers and preconditioners (LLNL)
Implemented in ANSI C using MPI
“Object Based”
GKK 9CASC
Collaboration ObjectivesBabel side:♦ demonstrate Babel technology ♦ feedback from library developers
Hypre side:♦ Automatically create Fortran bindings♦ Explore new designs 4Object-Oriented 4Component-Based
♦ Integrate other software 4C++ or F77
GKK 10CASC
Envisioned Architecture
F77 PythonC++
“official” hypreinterface (ANSI C)
MPI
GKK 11CASC
Approach
Identify minimal working subset of hypre♦ Structured Solvers
Create SIDL description Add base classes to create heirarchyTie generated code to existing hypre libraryIterate
GKK 12CASC
Problem: Creating wrong types
SIDL has 3 types of objects♦ interfaces - no implementations (pure abstract)♦ abstract classes - partial implementations♦ concrete classes - full implementations
Users were creatingabstract classes whenthey meant to createconcrete classes
interface Foo { int doThis( in int i );int doThat( in int i );
}
class Bar implements Foo { int doThis( in int i );
};
class Grille implements Foo { int doThis( in int i );int doThat( in int i );
};
GKK 13CASC
Solution: Fix The Grammar
Added the “abstract” keyword♦ Compiler issues error if a method is undefined and
class is not declared abstractAdded the “implements-all” keyword♦ declares all
methods as overridden
♦ saves user typing
interface Foo { int doThis( in int i );int doThat( in int i );
}
class Bar implements Foo { int doThis( in int i );
};
class Grille implements Foo { int doThis( in int i );int doThat( in int i );
};
interface Foo { int doThis( in int i );int doThat( in int i );
}
abstract
class Grille implements-all Foo// int doThis( in int i );// int doThat( in int i );
class Bar implements Foo { int doThis( in int i );
};
class Grille implements Foo { int doThis( in int i );int doThat( in int i );
};
interface Foo { int doThis( in int i );int doThat( in int i );
}
abstract class Bar implements Foo { int doThis( in int i );
};
{
};
GKK 14CASC
Problem: Managing all the Files
Babel creates many source files
foo.sidl
foo.f
foo_ior.c
foo_ior.h foo_skel.h
foo_skel.cc
foo_impl.h
foo_impl.ccfoo_stub.c
foo_stub.h
one set for eachclass & interface
GKK 15CASC
Solution: Babel Generates Makefile Macros
A “babel.make” file is generated
Users include it into their own makefiles♦ They control the build rules♦ We provide the file names
IORSRCS = foo_ior.c \bar_ior.c \grille_ior.c
IORHDRS = foo_ior.h \bar_ior.h \grille_ior.h
GKK 16CASC
Problem: Incremental Development
Library Developer would do the following:♦ write SIDL file♦ run Babel to generate bindings♦ hand edit “Impl” files to call their library code
#include “mylib.h”
int impl_Foo_doThis( Foo * self, const int i ) {
return mylib_Foo_doThis( (mylib_Foo*) self->userdata, i );
}
GKK 17CASC
Problem: Incremental Development (2)
Now assume this was done for 20 classes, each with 20 methods.Now assume a class needed a 21st methodBabel would regenerate all files and wipe out Developer’s edits#include “mylib.h”
int impl_Foo_doThis( Foo * self, const int i ) {
return mylib_Foo_doThis( (mylib_Foo*) self->userdata, i );
}
GKK 18CASC
Solution: Code Splicing
Added preservation of developer’s editsCode Splicer works line-by-line ♦ interleaves old code into new code♦ looks for begin-end pairs embedded in comments/* DO NOT DELETE splicer.begin( user-includes ) */#include “mylib.h”/* DO NOT DELETE splicer.end( user-includes ) */
int impl_Foo_doThis( Foo * self, const int i ) {/* DO NOT DELETE splicer.begin( Foo_doThis ) */return mylib_Foo_doThis(
(mylib_Foo*) self->userdata, i );
/* DO NOT DELETE splicer.end( Foo_doThis ) */}
GKK 19CASC
Results
Call hypre♦from C, F77, or C++♦on SPARC Solaris or DEC/OSF♦(more languages & platforms coming)
No interference with MPIBabel overhead within runtime noise
GKK 20CASC
Best Result: Change of Architecture
MPI
“official” hypreinterface (ANSI C)
F77 PythonC++ Python
MPI
F77 C++ANSI C
Babel Runtime
“official” interface
GKK 21CASC
Reasons for Change
Babel enforces regularity in codeLiked automatic reference counting Excellent compromise between:♦ Wanting
polymorphism and OO techniques
♦ Wanting all ANSI C for maximum portability
Liked using the toolNo Hand F77 bindings♦ incompatible♦ outdated
Preferred discussing designs in SIDL♦ easy for email♦ impossible to mix
implementation & interface
Convinced of Babel’s longevity
GKK 22CASC
Current & Future Work
Language Support♦ Current: C, C++, F77, Python (Client)♦ Coming: Python(Server), Java, F90, Matlab
Platform Independence♦ Implies RMI / Distributed Computing♦ SOAP
Parallel Data Redistribution Babelization efforts in LLNL♦ hypre♦ SAMRAI♦ ALPS
GKK 23CASC
Our Websitehttp://www.llnl.gov/CASC/components♦Alexandria (Component Repository)♦Quorum (Online Voting)♦Generic Parallel Redistribution
hyprehttp://www.llnl.gov/CASC/hypre
GKK 24CASC
UCRL-VG-140349 Rev 1
Work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract W-7405-Eng-48
GKK 25CASC
Key to Babel’s Interoperability...
SIDLScientific Interface
Definition Language
IORIntermediate Object
Representation
XMLeXtensible Markup
Language
Human Compat
b Compatible
Compiler Compatibleible
We
GKK 26CASC
CORBALanguage IndependentWide Industry AcceptancePrimarily RemotingArchitecture
COMLanguage IndependentMost Established In Process OptimizationNetwork Transparent
Enterprise Java Beans (EJB)Platform IndependentRuns wherever Java does
Business Component Frameworks
GKK 27CASC
Business Component FrameworksScience
CORBALanguage IndependentWide Industry AcceptancePrimarily RemotingArchitectureHuge StandardNo In-Process Optimization
COMLanguage IndependentMost Established In Process OptimizationNetwork Transparentnot Microsoft TransparentRelies on sophisticated development tools
Enterprise Java Beans (EJB)Platform IndependentRuns wherever Java doesLanguage SpecificPotentially highest overhead
All The AboveNo Complex IntrinsicDatatypeNo Dynamic Multidimensional ArraysNo Fortran77/90/95 bindingsNo Parallel ComponentsNo Concept of SPMD Programming
